Rock drill



Sept. 22, 1942. J. c. CURTIS ROCK DRILL Original Filed July 2, 1938 b mm, W NMN w mkwm a MS flu a a I n 0 I w W W I ,,4\\\ s a J/ Patented Sept. 22, 1942 ROCK DRILL John 0. Curtis, Claremont, N. H., assignor to Sullivan Machinery Company, a corporation of Massachusetts Original application July 2, 1938, Serial No. 217,287. Divided and this application May 31,

1940, Serial No. 338,027

3 Claims.

This invention relates to rock drills, and more particularly to improvements in rock drills of the self-supporting stoper type.

An object of this invention is to provide an improved rock drill having improved supporting means for supporting and guiding a drill steel hammer motor with respect to the work in an improved manner. together with improved feeding means associated with the supporting means for eifecting feed of the hammer motor. Another object is to provide an improved rock drill of the selfsupported stoper type having improved means for supporting the drill at the working face as well as at its rear end abutment so that an extremely stable support is attained. Still another object is to provide an improved extensible supporting structure for a rock drill on which a hammer motor is guided and embodying fluid actuated means for extending the supporting structure, together with improved fluid actuated means for feeding the hammer motor relative to the supporting structure. A still further object is to provide in a rock drill of the above character improved means for supporting and guiding the hammer motor so that in the event of a broken drill steel the possibility of the drill falling away from the work'is prevented even when the operator releases his grasp on the supporting handle of the drill, and as a result, possibility of injury to the operator due to such falling away of the drill is substantially eliminated. Yet another objectis to provide an improved automatically acting means for preventing the accidental dropping away of the drill from the work in the event of the failure of the fluid supply to the drill supporting means. These and'other objects and advantages of the invention will, however, hereinafter more fully appear in the course of the following description and as more particularly pointed out in the appended claims.

This application is a division of my copending application Serial No. 217,287, filed July 2, 1938, which has now become abandoned.

In the accompanying drawing there is shown for purposes of illustration one form which the invention may assume in practic In this drawing:

Fig. 1 is a view in longitudinal vertical section showing the improved supporting, guiding and feeding structure constructed in accordance with an illustrative embodiment of the invention, parts being shown in elevation to simplify illustration.

Fig. 2 is an enlarged detail sectional view taken on line 2-2 of Fig. 1.

Fig. 3 is a detail sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is a detail sectional view taken on line 4-4 of Fig. 2.

Fig. 5 is an enlarged sectional view taken sub stantially on line 5-5 of Fig. l.

Fig. 6 is a fragmentary elevational view of the throttle valve shown in Fig. 5.

Fig. 7 includes a series of fragmentary sectional views taken in the plane of line 1-1 of Fig. 5, showing the throttle valve in different positions as indicated at a. b and c.

Fig. 8 includes a series of fragmentary sectional views taken in the plane of line 8-8 of Fig. 5, showing the throttle valve in different positions as indicated at a, b and c.

Fig. 9 is a detail vertical sectional view showing the throttle valve and forward feed passage, the view taken in the plane of the line 8-8 of Fig. 5.

In the illustrative embodiment of the invention, the drill hammer motor is generally designated l and the improved supporting, guiding and feeding structure is generally designated 2. The rock drill is herein of the self-supporting stoper type, although it will be evident that certain features of the invention may be embodied in rock drills of various other types.

The hammer motor I is of the conventional reciprocating piston hammer type comprising a motor cylinder 3 containing a usual reciprocatory hammer piston for delivering impact blows to the shank of a drill steel 4 suitably supported within a front chuck housing 5. The motor cylinder has a usual rear head block 6 containing a throttle valve mechanism generally designated 1. The rear head block and front chuck housing are suitably secured to the motor cylinder in any conventional manner, as by usual side rods 8. As the internal structure of the hammer motor and the mode of operation thereof are well known to those skilled in the art, detailed description and illustration thereof are herein unnecessary.

Now referring to the improved supporting, guiding and feeding structure 2, it will be noted that contained in a tubular feed cylinder 9 is a reciprccable feed piston l0 having a tubular piston rod II. This piston rod extends rearwardly through the packed rear head It of the feed cylinder 9 and and has formed therein a piston chamber l3 having a rear head It and containing a reciprocable piston IS, the latter having its piston rod I6 telescopically arranged with respect to the piston rod II and extending forwardly through a usual packing I! supported within the feed piston ID. The hammer motor .the front chuck housing points arranged is mounted'on the feed cylinder 9 in parallel relation to the piston rods. and, in this instance, has a laterally located, integral boss-like portion |8 formed with stepped bores l9 and 26. and the forward end of the feed cylinder 9 is received in the bore l9 and provided with a front flange 2| engaginga shoulder 22 at the juncture of the bores Arranged in the bore and engag ng the flange 2| is a plate 23 held in position w1th1n th e bore by means of a block 24 projecting within the bore 20 and abutting the forward face of the plate. The plate 23 and block 24 are held in position within the bore, and the flange 2| is held in position against its shoulder by means of suitable side bolts. Arranged within the block 24 is a gland member 26 for holding a cup leather 21 in position against the plate 23 and for maintaining a packing 28 under compressionso that the cup leather and packing have fluid-tight sealing engagement with the exterior surface of the piston rod l6. It will be evident that the cup leather and packing may be readily replaced when worn simply by releasing the bolts and removing the block 24 forwardly from the bore 20, and, in this manner, access to the cup leathers of the feed piston H1 i made possible. The packing |1 sealingly engages the per1phery of the piston rod l6 and is designed to prevent leakage therealong, but in the event of any leakage past this cup leather along the piston rod into the piston chamber |3 in advance of the piston I5, the piston chamber is connected to atmosphere through a vent passage 36 in the piston rod l6. The forward end of the piston rod I6 is formed with an abutment engaging point 3|, while secured to the rear head H at the rear end of the piston rod II is an abutment engaging point 32, these abutment engaging in alinement with the axes of the piston rods II and I6 and adapted to engage suitable extraneous abutments at the opposite ends of the drill. I

The throttle valve mechanism 1 comprises a throttle valve of cylindric form rotatably mounted in a bore 36 formed within the rear head block 6 of the hammer motor. This valve have a valve stem 31 to which is secured an operating handle 38. The throttle valve is made hollow at 39 and pressure fluid is adapted to be supplied to the hollow interior of the throttle valve through a usual supply connection 49. Leading from the valve bore 36 is a forward feed passage 4| connected through passages in the motor cylinder and chuck housing to a forward feed port 42 communicating with an annular space 43 formed between the plate 23 andthe block 24, as shown in Fig. l. The pressure space 43 sages 44 in the plate 23 with the piston chamber of the feed cylinder 9 at the front side of the feed piston Ill; and the throttle valve 35 has a port 45 and connected slot 46 communicable with the passage 4|. Also communicating with the valve bore is a motor supply passage 41 leading to the distribution means of the hammer motor and the throttle valve has a passage 48 communicable with the passage 41. The throttle valve is exteriorly grooved at 49 (see Fig. 6) for connecting the forward feed passage 4| with the motor supply passage 41, thereby to permit venting of the feed through the motor exhaust. Also communicating with the valve bore is a passage 58 for supplying pressure fluid to the piston chamber |3 for the drill supporting piston l5, and the valve is connected through a series of pashas ports 5| and 52 communicating ,with the passage so that whenever pressure fluid is supplied to the throttle valve through the supply connection 40 it is concurrently supplied to the passage 56. As shown in Fig. 3, the passage 56 communicates with a threaded bore 53 in the head block 6, and threaded in this bore is a casing 54 of an auxiliary control valve 55. The valve casing 54 has a valve bore 56 containing the valve which is herein of the rotary type and provided with an operating handle 51. The valve has axial bores 58 and 59 of different diameters, and formed at the juncture of these bores is a valve seat 60 on which a plunger type check valve 6| is adapted to seat, the valve 6| being reciprocably mounted in the larger bore 59 and constantly urged towards its seat by a spring 62.

The bore 58 is communicable, through a port 63 in the valve, with a passage 64 communicating with the passage 50. When the check valve 6| is unseated, pressure fluid is adapted to flow from the passage 50, through passage 64, passage 63, bores 56, 59 to a space 65 formed in the valve casing at one end of the valve, and the valve 55 has a longitudinal groove 66 which connects this space with a passage 61. The passage 61 communicates with a threaded bore 66 in the valve casing, and threadedly connected within this bore is a conduit 69 connected to a passage 10 in the head member l4 of the feed piston rod. Pressure fluid is supplied through this conduit 69 to the piston chamber |3 at the rear side of the piston |5 when pressure fluid is supplied to the supply connection 40, for a purpose to be later explained. Formed on the exterior of the valve 55 is 'an exhaust groove 1| for connecting the passage 61 to exhaust when the valve 55 is rotated into its opposite position.

As previously mentioned, the improved rock drill is of the stoper type, and, in this instance,

has rigidly fixed to the motor cylinder 3 and projecting laterally from the motor, a supporting or holding handle 12 having a grasping portion 13 adapted to be grasped by the operator in the positioning and supporting of the drill.

The mode of operation of the improved rock drill will be clearly apparent from the description given. The drill is operated in the manner of a conventional stoper drill with the operator grasping the grasping portion of the supporting handle 12 and the rear end abutment point 32 engaging a suitable extraneous abutment. When the drill steel 4 is suitably positioned with respect to the working face, pressure fluid may be supplied from any suitable pressure fluid source to the supply connection 40 of the drill, and, since the conduit 69 communicates with the supply connection 40 through the passages 5| and 52 in the throttle valve, pressure fluid may flow through the passage 50 past the auxiliary valve 55 and check valve 6|, through the space 65 and groove 66 and thence through passage 61 and conduit 69 and through the passage 10 to the rear side of the drill supporting piston I5. It will be evident that the check valve 6| will close when the pressure at the rear side of the supporting piston attains a certain value less than line pressure, and will remain closed unless and and passages 44 tothe pistonchamber of the? eed cylinder 9 at the forward side of the feed; l0. Pressure fluid acting on the rear area of the plate 23 effects movement of th ston on the feed cylinder 9 moves forwardly therewith to elfect feeding of the drill steel toward the work. The operator then rotates the throttle valve 35 from the position indicated at b in Figs. 7 and 8 to the position indicated at c in those figures, and pressure fluid is then supplied through port 48 to the supply passage 41 of the drill hammer motor, so that the drill steel is percussively actuated. The supply of pressure fluid to the piston chamber l3 at the rear side of the drill supporting piston l5 may be cut off or regulated by the auxiliary control valve 55 in an obvious manner. In the event of failure of pressure fluid supply to the drill supporting piston IS, the check valve 6! serves automatically to prevent the escape of the pressure fluid in the pressure chamber H4 at the rear side of the drill supporting piston, so that the drill is automatically prevented from dropping away from the work. When the control valve 55 is turned into its opposite position, the piston chamber I3 at the rear side of the drill supporting piston is vented to atmosphere through the exhaust groove H. When the throttle valve 35 is rotated into the position indicated at a in Figs. 7 and 8, the feed is vented to atmosphere through the passage 4|, groove 49 on the throttle valve and the motor supply passage 41., the latter connected to atmosphere through the motor exhaust when the hammer motor is shut down. In the event of breakage of the drill steel at a point near the front chuck housing of the hammer motor outside of the drill hole, the drill is prevented from falling away from the work even when the operator has released his grasp from the supporting handle 12 since the drill is at all times supported by the piston rods II and I6, respectively firmly engaging the rear extraneous abutment and the working face, and as a result, injury to the operator, due to the falling of the drill away from the work, is prevented.

As a result of this invention it will be noted that an improved rock drill is provided having improved supporting and guiding means for the drill hammer motor whereby the drill is supported at two widely spaced points-at its rear end and at the working face. It will further be noted that by the provision of the extensible supporting structure for the hammer motor an improved stoper rock drill of the self-supporting type is provided, thereby preventing falling way of the drill from the working face even when the supporting handle of the drill is released by the operator or in the event of a broken drill steel, and, as a result, preventing injury to the operator due to such falling away of the drill. It will further be evident that by the provision of the e cylinder 9 forwardly relative to the piston-,rnclfiii II and I6, and the drill hammer motor mountedline to the drill supporting cylinder,v accidental dropping away of the drill fromthework in the event of the failure-of tii'e;fluid supply is auto matically prevented. Other uses andsadvantages of the improved rock drill will be clearly apparent to those skilled in the art.

While there is in this application,- despribed one form which the invention'may assunijein practice, it will be understood that this iorin'of the same is shown for purposes 'o'if illus ,trationjzand that the invention may be modified .i fand' embodied in various other forms without departing-from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

'1. In a rock drill, in combination, a steel actuating motor, a fluid actuated supporting structure for said motor comprising oppositely movable fluid actuated elements engageable with extraneous abutments, a manually operable throttle valve mechanism embodied in said motor for supplying pressure fluid to said supporting structure to effect relative opposite movement of said elements, an auxiliary manually operable control valve in the fluid supply line between said throttle valve mechanism and said supporting structure, and means embodied in said auxiliary valve for automatically trapping the fluid in said supporting structure in the event of the failure of the fluid supply to the throttle valve mechanism.

2. In a rock in combination, a steel actuating motor, a, fluid actuated supporting structure for said motor comprising oppositely movable fluid actuated elements engageable with extraneous abutments, fluid actuated means for feeding said motor along said supporting structure, a manually operable throttle valve mechanism embodied in said motor for supplying pressure fluid to said supporting structure to efl'ect relative opposite movement of said elements and for supplying fluidto said feeding means to effect feed, and an auxiliary manually operable control valve in the fluid supply line between said throttle valve mechanism and said supporting structure for controlling fluid flow to said supporting structure independently of any control of said feeding means.

3. In a rock drill, in combination, a steel actuating motor, a fluid actuated supporting structure for said motor comprising oppositely movable fluid actuated elements engageable with extraneous abutments, fluid actuated means for feeding said motor along said supporting structure, a manually operable throttle valve mechanism embodied in said motor for supplying pressure fluid to said supporting structure to effect relative opposite movement of said element and for supplying fluid to said feeding means to eflect feed, an auxiliary manually operable control valve in the fluid supply line between said throttle valve mechanism and said supporting structure for controlling fluid flow to said supporting structure independently of any control of said feeding means, and means embodied in said auxiliary valve for automatically trapping the fluid in said supporting structure in the event of failure of the fluid supply to said throttle valve mechanism.

JOHN C. CURTIS.

automatically acting check vafie'in-the supply Patent"'No; 2,296,816.

cminncnm: 0F CORRECTION.

JOHN C. CURTIS.

It is hereby certified that error appears in the printed specification of the above numbered patent'requiring correction as follows: Page 3, second column, line 511., beginning with "2. In a rock drill," strike out all September 22, 1%2.

to and including the words and period "feeding means. in line 50, com-.

prising claim 2, and for the claim now numbered "5" read --2--;in the heading to the printed specification, line 9, for "5 Claims read --2 Claims; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.-

Signed and sealed this 15th day or April, A. n. 19b5,

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

